\documentclass{article}
%\usepackage{pgfplots}
%\pgfplotsset{compat=newest}
%\pgfplotsset{plot coordinates/math parser=false}
\usepackage{setspace,subfigure}
\usepackage{tikz}
\usetikzlibrary{plotmarks}
\usetikzlibrary{lindenmayersystems}
\usetikzlibrary{decorations.pathmorphing}
\usepackage{geometry}
\geometry{verbose=false,papersize={14in,8.5in},body={14in,8.5in},marginratio={4:3, 2:3}}% marginratio={horizontal ratio,verticalratio}
\begin{document}
\thispagestyle{empty}
\null\vspace{0pt}
\hspace{0pt}
\begin{tikzpicture}
\draw plot[only marks,mark=*,mark size=0.5pt] file{ntpscontour.txt}; % original nodes
\draw[red] plot[only marks,mark=*,mark size=4pt] file{ntpsskeleton.txt}; % skeleton nodes
\end{tikzpicture}
\end{document}
